Orthodontic appliances are available in different kinds. Some appliances are designed for children and youth, and serve the influence the growth of the jaw. They are for instance known as a splint and as a trainer. Other appliances serve to displace individual teeth, relative to neighbouring teeth. These appliances are, in most cases, characterised by the presence of brackets located on the individual teeth. The brackets are typically coupled by means of a wire member, which will put a force on a tooth that is displaced and to be shifted relative to neighbouring teeth. In dependence of the stage of treatment, the material and thickness of the wire member is chosen by an orthodontist. The treatment therein usually starts with a wire member that exerts a small force on the teeth. This small force reduces as the teeth displace over time under its influence. Subsequently, normally once the force becomes too small to further displace the teeth, the wire member is exchanged. Generally, a thicker wire member is inserted, which results therein that the force acting on the teeth will become again higher.
Moreover, the wire member is tuned to one or more individual teeth. This tuning is also known as activation. In this activation process, an orthodontist modified the shape of the wire member locally, to obtain a desired moment of force. Herein, the desired moment of force not merely is characterised through its magnitude (for which the material and size of the wire member is primarily responsible) but also the orientation. The moment of force may be exerted in 6 dimensions: along the three carthesian axes, and according to three rotational orientations. While in the following reference will be made to ‘force’, the skilled person will understand that ‘force or moment of force’ is actually a more accurate reference.
This well-known type of orthodontic appliances has the difficulty of a precise force setting as a disadvantage. The skill of the orthodontist defines the force exerted on the teeth. But the wire member is subject to unintended deformation in the course of use. Moreover, which is often quite problematic, the wire member will exert a force on a misplaced tooth, but also a counterforce on neighbouring teeth. This counterforce may well be undesirable, in that a correctly positioned tooth is made subject to a force into a certain direction. As a consequence, such tooth may get a displacement, with all complications thereof.
An appliance proposal is disclosed in WO2009/126433A1, which tries to solve these problems by exerting forces on individual teeth by means of separate force exertion means for each tooth. The disclosed appliance comprises a polymeric body shaped in accordance with the jaw. Individual wire members are locked into said polymeric body and extend out of said body towards individual brackets on individual teeth. The wire members optionally comprise flexible springs allowing for longitudinal movement (i.e. in a direction generally along the direction of extension of the wire members away from the polymeric body). Therewith tensile or compressive forces in the longitudinal direction can be achieved. Herewith, both intrusive and extrusive forces could be applied on the teeth. The individual wire members are coupled to the brackets, particularly via magnetic couplings, and on the basis of a first and second coupling with complementary shapes.
However, the wire members of the disclosed appliance appear even more sensitive to deformation than the wire member of the existing appliances running along the teeth. This sensitivity is even more enhanced in that the polymeric body with the wire members is removable. When putting the removable section back into the mouth, all individual wire members require coupling with corresponding brackets. If some of the wire members are rather flexible and do not fit immediately, a user could easily deform some of those wire members. Moreover, the wire members run the risk of deformation under a cleaning operation with for instance a tooth brush.
It is already for this reason not surprising that the disclosed appliance is not known, i.e. the disclosed appliance appears an idea, but is not recognized as a commercially feasible product.
A further proposal for an appliance is known from WO2011/036249A1. The known appliance comprises an orthodontic working arch wire for moving at least one tooth of a dental arch of a patient to be treated from a first spatial configuration to a second spatial configuration, including an element for connecting to the tooth to be treated, which is intended to be attached onto the tooth being treated by snap-fitting onto a bracket glued onto one of the surfaces of said tooth. The working arch wire is rigid and the connecting element is movable relative to the orthodontic working arch wire by elastically deformable connecting means. The dental arch or body would be replaced in subsequent stages of the treatment, so as to redefine the force on the tooth or teeth. However, specific channels are deemed necessary for clipping a tool needed to position the body in the patient's mouth. That looks awkward in practice.